STANDARDIZED  STREET  WIDTHS 


Mr.  John  Nolen 
F.  A.  S.  L.  A.  Cambridge ,  Mass. 

If  we  are  to  remedy  the  municipal  ills  from  which  we  now 
suffer,  some  large  physical  changes  in  American  cities  are 
absolutely  necessary  and  inevitable.  Nevertheless,  perma¬ 
nent  progress  in  city  planning  will  not  result  usually  from 
spectacular  schemes  for  the  sudden  transformation  of  our 
cities,  nor  from  revolutionary  programs  and  proposals.  Ad¬ 
vances  will  come  more  often  from  a  patient  but  open-minded 
and  scientific  study  of  such  problems  as  are  represented  by 
the  title  of  this  paper,  followed  by  a  close  co-ordination  of 
one  subject  with  another  in  a  comprehensive  plan,  thus  rec¬ 
ognizing  the  unity  of  the  city  and  the  inter-relation  of  all 
its  parts. 

It  would  not  be  difficult  to  convince  anyone  not  already 
convinced  —  if  such  there  be  —  of  the  importance  of  fixing 
street  widths  more  intelligently  and  discriminatingly.  At 
the  present  time  an  average  of  twenty  to  forty  per  cent  of 
the  total  area  of  cities  is  devoted  to  streets,  rising  in  the 
case  of  Washington,  D.  C.,  to  fifty-four  per  cent.  There¬ 
fore,  even  a  slight  variation  in  the  width  of  the  streets  of  a 
city  becomes  a  matter  of  importance.  Consider,  for  exam¬ 
ple  what  an  excess  of  two  feet  in  the  width  of  the  fourteen 
hundred  miles  of  paved  streets  of  Philadelphia  would  involve 
in  the  cost  of  land  and  paving !  On  the  other  hand  —  and 
here  the  lack  of  intelligent  and  discriminating  action  has 
even  graver  aspects  —  consider  what  the  lack  of  a  few  feet  in 
the  width  really  necessary  for  streets  in  Philadelphia  already 


P 


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involves!  It  involves  directly  the  expenditure  of  enormous 
sums  of  money  for  street  widening,  or,  indirectly,  of  much 
greater  sums,  practically  incalculable  in  amount,  as  the  pen¬ 
alty  for  conditions  which  still  appear  to  our  too  timid  minds 
virtually  unchangeable. 

The  evils  of  the  present  system  of  fixing  street  widths  are 
acute.  They  demand  prompt  but  careful  examination  and 
correction.  What,  then,  are  the  causes  of  the  existing  diffi¬ 
culties  in  this  matter  of  street  widths  and  what  are  the  reme¬ 
dies?  Some  ‘students  of  this  subject  are  of  the  opinion  that 
the  evils  are  due,  in  part  at  least,  to  a  standardization  of 
street  widths ;  to  the  fact  that  city  councils  or  other  munici¬ 
pal  authorities  have  heretofore  fixed  upon  a  certain  number 
of  feet,  usually  forty,  fifty  or  sixty  feet,  as  the  width  for  all 
streets.  Undoubtedly  such  action  has  proved  a  handicap  to 
many  a  city.  But  is  the  standardization  itself  the  evil?  Is  it 
not  the  arbitrary  and  unintelligent  character  of  that  stan¬ 
dard;  and  is  not  the  remedy  another  standard,  or  other 
standards,  rather  than  the  abandonment  of  the  principle  of 
standardization?  Is  there  not  danger  of  reacting  too  far, 
or  of  reacting  in  the  wrong  direction?  The  remedy  for  a 
stupid  standardization  of  street  widths  is  not  likely  to  be 
found  in  the  abandonment  of  all  standards,  but  in  the  adop¬ 
tion  of  more  intelligent  standards. 

It  would  seem  that  street  widths  could  be  satisfactorily 
standardized  because  the  facts  upon  which  such  widths  rest 
are  capable  of  definite  classification  and,  furthermore,  be¬ 
cause  it  is  practicable  to  collect  scientific  data  concerning 
these  facts  and  from  this  data  to  reason  to  sound  conclu¬ 
sions  with  a  considerable  degree  of  confidence.  While  these 
facts  are  numerous  and  varying,  they  are  not  more  so  than 
those  connected  with  the  cutting  of  metals,  or  some  of  the 
other  operations  that  have  been  so  successfully  standardized 
in  the  industrial  world  in  recent  years. 

What  are  the  facts  which  should  determine  street  widths? 
They  are  ( 1 )  the  width  required  for  “  a  line  of  vehicles,” 
thus  fixing  roadway  units;  (2)  the  width  required  for  “  a 


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line  of  pedestrians,”  thus  fixing  sidewalk  units;  (3)  the  clas¬ 
sification  of  the  streets  of  a  city  according  to  the  traffic  re¬ 
quirements  put  upon  them,  or  the  other  functions  that  they 
are  to  serve;  and  (4)  an  estimate  of  the  present  and  future 
traffic  of  the  streets  of  any  given  class,  the  width  required 
to  meet  that  traffic,  and  then  the  standardization  of  that 
width. 

(1)  It  is  not  yet  possible  to  fix  with  scientific  accuracy 
the  width  required  for  a  line  of  vehicles,  partly  because  the 
data  as  to  the  actual  average  width  of  present  day  vehicles 
is  inadequate,  and  partly  because  that  wfidth  is  just  now  in 
process  of  change,  due  mainly  to  the  increasing  size  and  use 
of  the  motor  truck.  Nevertheless,  the  conclusions  on  this 
point  are  already  fairly  definite.  The  difference  is  repre¬ 
sented  by  about  one  foot.  One  set  of  investigators  holds 
that  nine  feet  or  thereabouts  should  be  fixed  as  the  width 
required  for  a  line  of  vehicles.  They  base  their  opinion 
upon  the  fact  that  some  motor  truck  bodies  to-day  have  a 
width  of  eighth  feet  and  that  the  tendency  of  manufacturers 
is  to  increase  the  width  of  trucks.  The  margin  for  safe  clear¬ 
ance,  taking  into  account  average  skill  in  driving,  would 
require  about  another  foot  for  each  line  of  vehicles,  making 
the  total  width  nine  feet.  Other  investigators  find  that  to¬ 
day  very  few  vehicles,  even  large  motor  trucks,  measure 
more  than  six  and  one-half  or  seven  feet  in  width,  and  that 
conditions  of  construction  or  laws  are  likely  to  place  a  limit 
upon  advantageous  width  close  to  seven  feet.  This  view  has 
the  support  of  some  of  the  vehicle  companies  who  hold,  in 
the  interest  of  the  manufacturer  and  user  of  trucks,  as  well 
as  the  public,  that  six  and  one-half,  or,  at  most,  seven  feet 
should-  be  the  maximum  width. 

It  is  not  the  purpose  of  this  paper  to  try  to  settle  finally 
the  width  required  for  a  line  of  vehicles  or,  indeed,  any  other 
fact  or  specific  point  connected  with  the  standardization  of 
street  widths.  The  purpose  is  merely  to  indicate  the  ad¬ 
vantages  and  necessity  for  such  standardization  and  to  sug¬ 
gest  some  reasonable  basis  for  it. 


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But  to  apply  further  the  method  suggested  above,  we  may 
assume  for  the  sake  of  making  the  application  definite,  that 
a  width  of  eight  feet,  the  present  working  figure  of  many 
of  the  best  practitioners,  is  sufficient  for  a  line  of  vehicles. 
As  a  matter  of  fact,  not  only  the  width  of  vehicles  but  also 
the  load  is  likely  to  be  standardized  by  law,  so  that  the 
engineer,  landscape  architect,  or  city  planner  will  have  a 
definite  maximum  figure  to  work  with.  These  limits  may 
have  exceptions,  but  the  exceptions  should  be  discouraged 
bJ  a  vehicle  license  tax,  which  would  increase  very  rapidly 
on  vehicles  above  certain  dimensions. 

In  addition  to  the  space  required  for  vehicles,  allowance 
must  be  made  on  many  streets  for  electric  cars.  Assuming 
double  tracking,  which  is  the  most  economical  method  usu¬ 
ally,  this  allowance  should  be  not  less  than  twenty  feet. 

(2)  Various  methods  have  been  devised  and  followed  for 
determining  the  width  of  sidewalks.  The  most  customary 
is  to  make  the  sidewalk  some  fixed  proportion  of  the  road¬ 
way.  In  some  cases,  following  this  method,  each  sidewalk 
is  one-half  the  width  of  the  roadway ;  in  others  one-third 
the  width  of  the  roadway.  The  latter  appears  to  represent 
the  most  frequent  practice.  This  method,  however,  appears 
arbitrary  and,  in  some  instances,  would  be  unsound,  because 
the  use  of  the  sidewalks  does  not  necessarily  increase  and 
diminish  with  the  amount  of  traffic  on  the  roadway.  How¬ 
ever,  the  custom  of  making  the  sidewalk  one-third  the  width 
of  the  roadway  has  proved  fairly  satisfactory  in  practice. 
For  example,  in  the  subdivision  of  a  one-hundred-foot  busi¬ 
ness  street  into  a  sixty-foot  roadway  and  twenty-foot  side¬ 
walks.  Fixing  the  width  for  a  line  of  pedestrians  at  two 
feet,  if  the  application  of  the  principle  to  pedestrians  does 
not  appear  too  academic,  this  allows,  on  a  street  with  a  total 
width  of  one  hundred  feet,  for  ten  lines  of  pedestrians  on 
each  of  the  twenty-foot  sidewalks.  The  proper  width  of 
sidewalks,  the  method  of  determining  that  width,  and  a  more 
rigid  control  of  encroachments  upon  sidewalks,  all  deserve 
more  attention  than  they  have  heretofore  received. 


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(3)  The  classification  of  the  streets  of  a  city  according 
to  the  traffic  requirements  put  upon  them  or  the  other  func¬ 
tions  that  they  are  to  serve  is,  of  course,  one  of  the  funda¬ 
mental  requirements  of  any  attempt  to  standardize  street 
widths.  European  countries  have  made  such  classifications. 
Here  are  the  figures  for  some  of  the  cities  of  England  and 
Germany. 

The  London  Traffic  Commission  made  five  divisions  as 


follows : 

Main  avenues . 140  feet 

First  class  arterial  streets .  100  “ 

Second  class  streets .  80  “ 

Third  class  streets .  60  “ 

Fourth  class  streets .  40  to  50  feet 


No  street  wras  to  be  less  than  forty  feet.  This  standard 
classification,  applying  to  London  and  its  suburbs,  is  a  great 
advance  over  the  London  Building  Act  of  1894,  which  put 
the  average  width  of  streets  “  in  the  public  interest  ”  at  forty 
feet  clear  or  twenty  feet  from  the  center  of  the  roadway  to 
the  nearest  external  wTall ;  and  the  Council  could  not  re¬ 
quire  a  greater  width  than  sixty  feet. 

The  standard  classification  for  German  cities  of  the  second 
size,  cities  like  Leipzig  and  Frankfort,  is  as  follows : 


Main  thoroughfares . 85  to  118  feet 

Secondary  thoroughfares . 50  to  80  “ 

Local  streets . 35  to  47  “ 


A  Prussian  law,  in  force  since  1875,  apparently  drawn  to 
meet  the  requirements  of  Berlin,  fixes  the  following  dimen¬ 
sions  for  the  laying  out  of  new  streets  and  for  the  altera¬ 


tion  of  old  ones : 

Main  thoroughfares . 95  feet  or  over 

Secondary  thoroughfares . 65  to  95  feet 

Local  streets . 40  to  65  “ 


The  width  of  streets  in  different  American  cities  varies 
greatly.  There  are  very  few  that  have  adopted  standards 


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for  the  classification  of  streets  according  to  traffic  require¬ 
ments.  Probably  the  best  classification  is  that  of  Washing¬ 
ton,  D.  C.,  which  is  as  follows: 


Main  thoroughfares . 160  feet 

Secondary  thoroughfares . 120  “ 

Local  streets .  60  to  90  feet 


The  German  city  standards,  given  above,  appear  to  be 
more  reasonable  and  logical  than  those  of  London  or 
Washington,  and  there  is  a  distinct  advantage  in  having 
more  or  less  range  within  each  classification,  as  against 
fixing  the  width  hard  and  fast  to  a  single  figure.  It  ought 
to  be  practical  to  classify  most  of  the  streets  of  a  city  either 
as  main  thoroughfares,  secondary  thoroughfares,  or  local 
streets,  and  to  apply  to  them  one  of  the  standard  widths 
adopted  for  their  respective  classifications. 

(4)  To  determine  such  classification,  however,  requires 
an  estimate  of  the  recent  and  future  traffic  requirements 
of  the  streets  of  any  given  class.  It  does  not  seem  wise  to 
begin  by  fixing  the  width  of  a  street  at  say  fifty  or  sixty 
or  one  hundred  feet,  and  then  apportioning  that  width  as 
favorably  as  may  be  between  roadway  and  sidewalk.  It  is 
better  to  begin  at  the  other  end  and  try  to  decide  what 
traffic  capacity  in  roadway  and  sidewalk  the  street  should 
provide  for,  thus  determining  which  class  it  falls  in ;  and 
then  applying  the  unit  of  measurement  adopted  for  car 
lines,  for  vehicles,  for  pedestrians,  for  trees,  etc.,  decide 
upon  the  required  width.  For  example,  here  are  three  illus¬ 
trations  of  this  method: 

I.  An  average  main  thoroughfare  is  to  have,  say, 


A  double  track  car  line . 20  feet 

6  lines  of  vehicles,  3  on  each  side  of  tracks,  8  feet  each  ...  48  “ 

20  lines  of  pedestrians,  10  lines  on  each  of  the  two  sidewalks, 

2  feet  each . 40  “ 

Total  for  an  average  main  thoroughfare . 108  “ 


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II.  An  average  secondary  thoroughfare  is  to  have,  say, 


A  double  track  car  line . 

4  lines  of  vehicles,  2  on  each  side  of  tracks,  8  feet  each  .  .  . 
16  lines  of  pedestrians,  8  lines  on  each  of  the  two  sidewalks, 
2  feet  each . 

Total  for  an  average  secondary  thoroughfare . 


20  feet 
32  “ 

32  “ 

84  “ 


III.  An  average  local  street  is  to  have,  say, 

Roadway  for  3  lines  of  vehicles,  8  feet  each . 24  feet 

12  lines  of  pedestrians,  6  lines  on  each  of  the  two  sidewalks, 

2  feet  each . 24  “ 

Total  for  an  average  local  street . 48  “ 


These  are  only  averages  and  are  given  simply  as  illus¬ 
trations  of  the  method  of  standardization  proposed  and  its 
application.  The  range  of  street  widths  for  such  a  classi¬ 
fication  might  be  as  follows: 


Main  thoroughfares  .  . 
Secondary  thoroughfares 
Local  streets . 


90  to  180  feet 
60  to  90  “ 

40  to  60  “ 


Such  a  standardization  would  naturally  differ  from  city 
to  city  as  conditions  and  requirements  differed.  Its  advan¬ 
tages  would  be  twofold:  first  in  fixing  the  range  of  normal 
street  requirements  of  three  or  more  important  classes ; 
secondly  in  definitely  and  consciously  trying  to  determine 
in  advance  to  which  class  a  particular  street  belonged.  Of 
course,  even  with  such  a  classification  there  would  be  many, 
many  exceptions,  —  special  streets,  having  special  require¬ 
ments  and,  therefore,  calling  for  special  provisions.  But  if 
no  standards  whatever  are  fixed  —  and  this  is  the  important 
practical  point  —  there  is  danger  that  the  normal  differen¬ 
tiation  of  the  streets  of  one  class  from  those  of  another 
will  be  constantly  overlooked,  or  that  private  interests 
through  pressure  and  influence  may  succeed  in  securing  ac¬ 
tion  which  is  in  conflict  with  the  public  requirements.  It 
was  largely  to  prevent  these  results  that  street  width 


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standards,  in  most  cases  unintelligent  and  undiscriminating, 
were  adopted  by  cities  in  the  past.  Where  no  standards 
whatever  have  been  adopted  many  illustrations  can  be  found 
of  the  abuses  that  have  crept  in,  particularly  the  failure 
to  allow  sufficient  street  width  for  main  and  secondary 
thoroughfares. 

In  the  discussion  thus  far  no  reference  has  been  made 
to  trees,  grass  strips,  or  other  planting  in  the  streets,  or 
of  space  set  aside  primarily  for  the  adornment  of  the  street 
or  for  insuring  the  benefits  of  light  and  air  and  an  appear¬ 
ance  of  spaciousness.  Such  reference  was  omitted  merely 
to  simplify  the  subject  and  bring  it  within  the  compass 
of  a  brief  paper.  Of  course,  trees  are  desirable  not  only 
in  residence  streets,  but  also  in  most  business  streets.  Of 
the  many  arguments  against  the  greater  use  of  trees  in  our 
business  streets,  the  only  sound  argument  in  most  instances 
is  that  there  is  no  room  for  them.  But  as  with  traffic  so 
with  trees.  The  same  method  should  be  applied.  If  we  are 
to  have  trees  we  must  determine  the  width  requirements  of 
a  line  of  trees,  or  two  lines  of  trees,  or  whatever  else  is 
needed.  Except  for  temporary  effects,  it  is  not  good  policy 
to  plant  trees  in  a  space  that  is  needed  for  roadway  or 
sidewalks ;  nor  is  it  good  policy  to  plant  one  or  more  lines 
of  trees  in  a  space  that  is  inadequate  for  their  successful 
growth.  If,  for  instance,  it  is  decided  that  six  feet  is  the 
minimum  space  in  which  a  line  of  trees  of  a  given  species 
can  flourish,  then  we  should  standardize  that  width  for  that 
species  of  tree  and  provide  it.  Exceptions  there  would  be 
undoubtedly  to  standards  for  trees  as  for  roadways  and 
sidewalks,  but  they  would  be  recognized  as  exceptions  and 
justified  because  of  exceptional  conditions.  Standards  can 
only  be  applied  profitably  to  the  normal,  but  in  such  mat¬ 
ters  as  street  widths  five-sixths,  perhaps  nine-tenths,  of  all 
cases  would  be  normal. 

The  traffic  and  use  of  many  city  streets  increase  from 
year  to  year,  tending  to  shift  some  streets  from  one  classi¬ 
fication  to  another.  How  to  provide  a  method  of  meeting 


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this  increase  is  a  difficult  question  to  answer.  To  begin 
with,  we  must  recognize  that  a  city  that  is  alive  has  growth, 
and  that  growth  makes  changes  from  time  to  time  neces¬ 
sary.  Street  widths  cannot  be  made  right  64  once  for  all.” 
The  utmost  foresight  must  be  exercised  and  then  adjust¬ 
ments  and  widenings  made  to  meet  new  conditions.  Street 
development,  like  most  other  features  of  city  planning,  is 
an  unending  process.  In  the  field  of  education,  the  unend¬ 
ing  character  of  the  process  was  expressed  by  the  boy  who 
inquired  at  a  public  library  for  a  book  which,  he  said,  was 
entitled  “  How  to  Get  Educated  and  How  to  Stay  So.” 
So  it  is  with  streets.  The  problem  is  how,  by  the  exercise 
of  skill  and  foresight,  to  design  and  arrange  them  to  fulfill 
their  functions  and  then  from  time  to  time  how  to  re-design 
and  re-arrange  them  to  meet  new  requirements.  In  the  case 
of  streets  where  increased  traffic  is  expected,  the  most  prac¬ 
tical  method  of  providing  for  it,  perhaps,  would  be  to  re¬ 
serve  some  extra  space  between  the  roadway  and  sidewalk, 
or  in  the  center  of  the  roadway,  or  between  the  sidewalk 
and  the  buildings,  utilizing  this  space  temporarily  as  an 
area  planted  with  trees  and  shrubs,  or  merely  with  grass. 

The  evils  that  might  follow  from  the  adoption  of  an 
undiscriminating  set  of  standards,  or  from  an  unintelligent 
application  of  a  discriminating  set,  have  not  been  over¬ 
looked.  They  might  be  serious.  But  it  is  my  opinion  that 
under  our  present  city  organization  such  evils  would  ordi¬ 
narily  be  less  than  those  that  almost  inevitably  follow  from 
a  lack  of  any  established  standards  and  from  the  policy 
of  determining  street  widths  piecemeal,  as  each  is  presented 
for  decision. 


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